The question of whether and then why Zipf’s law applies to city sizes is at the heart of the research. This study is focusing on whether Zipf’s rule remains true in a global context, encompassing all cities on the planet. Previous studies, including this one, depend mostly on traditional official statistics just as population and enumeration department forced city designations. Here we investigate the law further at the level of country discover that Zipf’s law is disregarded and varies in time and from country to country. Our research investigates whether the rule of Zipf applies to all situations globally. Zipf law applied to city numbers the outcome is the cities numbers for the first biggest country is double that of the second biggest country, Three times higher than that of the third-largest country, and so on. An urban system may be described by a Pareto exponent with a parameter (β) value of 1. The empirical validity of Zipf’s Law is assessed in this promoting research fresh data from 235 countries and two distinct estimate methods – conventional OLS, Rank-half rule, and the Wald test. Using this Methodology and data set we divided the data into three groups; Developed countries (HIC), Developing (MIC), and underdeveloped countries (LIC). 4 out of 65 developed countries obtained the β- values significantly, while approx. 25% got a higher value than unity. Eight MICs got values near to unity and approx. 18% got a value higher than our hypothesis of (β=1). Likewise, Underdeveloped nation two countries Yemen and DR Congo got statistically sig. a value equal to 1. Zipf law or Power Law is rejected for most of the countries, most the nations have value less than which implies that overall, there is more concentration, uneven dist. of population, more hierarchies are there in these maximum number countries. These countries have large cities which are more concentrated as compared to small and medium-sized cities. Supervisor:- Dr. Ahsan Ul Haq Satti